EUP3226JIR1

EUP3226 3A, Synchronous Step-Down Converter .. DESCRIPTION FEATURES The EUP3226 is a 1 MHz fixed frequency synchronous, current-mode, step-down dc-dc converter capable of providing up to 3A output current. The EUP3226 operates from an input range of 2.7V to 5.5V and provides a regulated output voltage from 0.6V to 5V. The internal synchronous power switch improves efficiency and eliminates the need for an external Schottky diode. The EUP3226 can be externally set for either forced PWM continuous mode or pulse skipping mode. Forced PWM operation provides very low output ripple voltage for noise sensitive applications while pulse skipping operation improves light load efficiency by reducing switching loss. The EUP3226 features short circuit and thermal protection circuits to improve system reliability. Internally soft-start avoids input inrush current during startup. The EUP3226 is available in TDFN 3mm × 3mm 10-pin package with the exposed pad and SOP-8 package with the exposed pad.










2.7V to 5.5V Input Voltage Range High Efficiency up to 96% 3A Available Load Current 57/35mΩ Integrated PFET/NFET Switches 1MHz Switching Frequency 100% Duty Cycle Low Dropout Operation Short Circuit and Thermal Protection Integrated UVLO and Power Good Excellent Line and Load Transient Response Available in 10-Pin 3mm × 3mm TDFN and SOP-8 (EP) Packages RoHS Compliant and 100% Lead(Pb)-Free Halogen-Free APPLICATIONS


High Performance DSPs, FPGAs, ASICs and Microprocessors Base Station, Telecom, and Networking Equipment Power Supplies ePC and NetPCs Typical Application Circuit Figure1. TDFN-10 Typical Application Circuit DS3226 Ver1.0 June 2014 1 EUP3226 Typical Application Circuit (continued) Figure2. SOP-8 (EP) Typical Application Circuit Pin Configurations Package Type Package Type Pin Configurations TDFN-10 Pin Configurations SOP-8 (EP) Pin Description PIN TDFN-10 SOP-8 (EP) DESCRIPTION NC 1 - LX 2,3 1 PG 4 4 EN 5 3 FB 6 6 SKIP 7 2 SVIN 8 - PVIN 9,10 7 No connection. Switch node connected to inductor. This pin is connected to the drains of the internal main and synchronous power MOSFET switches. Power good output signal. Logic high when regulator output is within ±10% of target output voltage. A pull-up resistor of 10kΩ to 100kΩ is recommended for most applications. Chip enable pin. Forcing this pin above 1.5V enables the part. Forcing this pin below 0.3V or floating it shut down the device. An internal 600kΩ resistor pull it down to ground. Feedback pin. Connect it to an external resistor divider to set output voltage. Operation Mode Select Input. Logic high selects pulse skipping mode, and logic low or floating chooses forced PWM mode. An internal 7µA current pull it down to ground. Analog input supply which is connected to PVIN through a low pass RC filter. Input voltage to the power switches. AGND - 5 Analog ground. PGND - 8 Power ground. Thermal Pad - - Ground.( Thermal pad is used as the ground of whole chip.) DS3226 Ver1.0 June 2014 2 EUP3226 Ordering Information Order Number Package Type EUP3226JIR1 TDFN-10 EUP3226WIR1 SOP-8 (EP) Marking xxxxx P3226 1A xxxxx P3226 1A EUP3226 □ □ □ □ Lead Free Code 1: Lead Free, Halogen Free Packing R: Tape & Reel Operating temperature range I: Industry Standard Package Type J:TDFN W:SOP (EP) Block Diagram Figure3. Block Diagram DS3226 Ver1.0 June 2014 3 Operating Temperature Range -40 °C to +85°C -40 °C to +85°C EUP3226 Absolute Maximum Ratings (1)          Input Supply Voltage(SVIN, PVIN) ----------------------------------------------- -0.3V to 6V EN, FB, SKIP ------------------------------------------------------------------------- -0.3V to 6V PG -------------------------------------------------------------------------------------0V to 6V LX Voltage ----------------------------------------------------------------- -0.3V to VPVIN+0.3V Junction Temperature -------------------------------------------------------------------150°C Package Thermal Resistance TDFN-10,θJA ---------------------------------------------------------------------------- 69°C/W SOP-8 (EP),θJA -------------------------------------------------------------------------- 60°C/W Storage Temperature ----------------------------------------------------------- -65°C to 150°C Lead Temp (Soldering, 10sec) ----------------------------------------------------------- 260°C Minimum ESD Rating -------------------------------------------------------------------±2kV Recommended Operating Conditions (2)   Supply Voltage ------------------------------------------------------------------- 2.7V to 5.5V Operating Temperature Range ----------------------------------------------- -40°C to 85°C Note(1): Stress beyond those listed under “Absolute Maximum Ratings” may damage the device. Note(2): The device is not guaranteed to function outside the recommended operating conditions. Electrical Characteristics PVIN=SVIN=VEN=5V, TA=+25°C,unless otherwise specified. The ● indicates specifications which apply over the full operatimg range -40°C to +85°C. The EUP3226 is 100% production tested at 25°C. Typical and temperature specifications are guaranteed by design and statistical characterizations. Symbol Parameter VIN UVLO UVLO_Hys IFB Input Voltage Range Input Undervoltage Lockout UVLO Hysteresis Feedback Current VFB Regulated Feedback Voltage ∆VOUT VLOADREG VPGH VPGL TPG VLPG IPG VENL VENH REN VSKIPL VSKIPH ISKIP IQ ISHDN DS3226 Output Voltage Line Regulation Output Voltage Load Regulation Power Good High Threshold Power Good Low Threshold Power Good Delay Time Power Good Low Voltage Power Good Leakage Current EN Input Low Voltage EN Input High Voltage EN Pull Down Resistor SKIP Input Low Voltage SKIP Input High Voltage SKIP Pull Down Current Quiescent Current Shutdown Current Ver1.0 June 2014 EUP3226 Min. Typ. Max. Conditions -40°C ≤TA≤+85°C Rising, -40°C ≤TA≤+85°C VFB=0.6V TA=+25°C -40°C≤TA≤+85°C VIN=3V to 5V ILOAD=100mA to 3A With Respect To VFB With Respect To VFB ● ● 2.7 2.25 ● -50 0.594 0.588 +7 -13 ISINK=1mA High Impedance, VPG=5V 2.45 200 0 0.600 0.600 0.15 0.1 +10 -10 32 0.1 5.5 2.65 +50 0.606 0.612 +13 -7 0.3 1 0.3 1.5 600 0.3 1.5 3 VFB=0.65V, VSKIP=5V or 0V VEN=0V 4 7 0.5 10 0.8 3 Unit V V mV nA V %/V %/A % % Cycles V µA V V KΩ V V µA mA µA EUP3226 Electrical Characteristics (continued) PVIN=SVIN=VEN=5V, TA=+25°C,unless otherwise specified. The ● indicates specifications which apply over the full operatimg range -40°C to +85°C. The EUP3226 is 100% production tested at 25°C. Typical and temperature specifications are guaranteed by design and statistical characterizations. Symbol fOSC Oscillator Frequency DMAX TON(Min) IPEAK INEG RLX RPFET RNFET TSD DS3226 Parameter Maximum Duty Cycle Minimum On Time Hside PCH Switch Peak Current Lside NCH Negative Current Limit LX Pull Down Resistor RDS(ON) of P-Channel FET RDS(ON) of N-Channel FET Thermal Shutdown Ver1.0 June 2014 Conditions VFB=0.55V,-40°C≤TA≤+85°C VFB=0V VFB=0.55V VSKIP =0V, FPWM Mode VEN=0V ILX=0.5A ILX=0.5A 5 Min. ● 0.8 EUP3226 Typ. Max. 1 380 100 100 5 -1 1.25 57 35 160 1.2 70 50 Unit MHz KHz % ns A A KΩ mΩ mΩ °C EUP3226 Typical Operating Characteristics CIN=22µF, COUT=22µF×2, L=2.2µH, VIN=5V, VOUT=1.2V, See Figure 1, TA=25°C, unless otherwise noted. DS3226 Ver1.0 June 2014 6 EUP3226 Typical Operating Characteristics (continued) DS3226 Ver1.0 June 2014 7 EUP3226 Typical Operating Characteristics (continued) DS3226 Ver1.0 June 2014 8 EUP3226 Typical Operating Characteristics (continued) DS3226 Ver1.0 June 2014 9 EUP3226 Application Information The EUP3226 uses a slope-compensated constant frequency, current mode architecture. Both the main (P-Channel MOSFET) and synchronous (N-channel MOSFET) switches are internal. During normal operation, the EUP3226 regulates output voltage by switching at a constant frequency and then modulating the power transferred to the load each cycle using PWM comparator. The duty cycle is controlled by three weighted differential signals: the output of error amplifier, the main switch sense voltage and the slope-compensation ramp. It modulates output power by adjusting the inductor peak-current during the first half of each cycle. An N-channel, synchronous switch turns on during the second half of each cycle. When the inductor current starts to reverse in pulse skipping mode operation or when the PWM reaches the end of the oscillator period in forced PWM operation, the synchronous switch turns off. Soft-Start The EUP3226 has an internal soft-start circuit to limit the inrush current and output voltage overshoot during startup. The soft-start time is about 800µS. Short-Circuit Protection Output Overvoltage Protection The output voltage is monitored by a comparator through FB pin. It guards against transient overshoots >10% by turning the main switch off . Input Undervoltage Lockout The undervoltage lockout circuit prevents device misoperation at low input voltages. It prevents the converter from turning on the main and synchronous switches under undervoltage state. Thermal Protection and Lockout The internal thermal protection and lockout circuit prevents device in the event that the maximum junction tempetaure is exceeded. If the device temperature is higher than 160°C (typical), it will be shut down. Only if the power is reprovided or the EN pin is reactived can the device rework. Inductor Selection The EUP3226 typically uses a 2.2µH output inductor. The output inductor is selected to limit the ripple current to some predetermined value, typically 20%~40% of the full load current at the maximum input voltage. Large value inductors lower ripple currents. Higher VIN or VOUT influence the ripple current as shown in equation. Ver1.0 June 2014 10 L =  V  1 − OUT V OUT  (f)(L) V IN  1     The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation. The DC-resistance of the inductor directly influences the efficiency of the converter. Therefore for better efficiency, choose a low DC-resistance inductor. CIN and COUT Selection In continuous mode, the source current of the top MOSFET is a square wave of duty cycle VOUT/VIN. The primary function of the input capacitor is to provide a low impedance loop for the edges of pulsed current drawn by the EUP3226. A low ESR input capacitor sized for the maximum RMS current must be used. The size required will vary depending on the load, output voltage and input voltage source impedance characteristics. A typical value is around 22µF. The input capacitor RMS current varies with the input voltage and the output voltage. The equation for the maximum RMS current in the input capacitor is: I As soon as the output voltage drops below 50% of the nominal output voltage, the converter switching frequency and the current limit are reduced. DS3226 ∆I RMS =I OUT ×  V V OUT ×  1 − OUT  V V IN IN      The output capacitor COUT has a strong effect on loop stability. The selection of COUT is driven by the required effective series resistance (ESR). ESR is a direct function of the volume of the capacitor; that is, physically larger capacitors have lower ESR. Once the ESR requirement for COUT has been met, the RMS current rating generally far exceeds the IRIPPLE(P-P) requirement. The output ripple ∆VOUT is determined by:  ∆VOUT ≅ ∆I L  ESR +  8fC     OUT  1 When choosing the input and output ceramic capacitors, choose the X5R or X7R dielectric formulations. These dielectrics have the best temperature and voltage characteristics of all the ceramics for a given value and size. Output Voltage Programming The output voltage is set by a resistive divider according to the following formula, where RFB1 value is kept 150KΩ:   0.6  R FB2 = R FB1  V  0.6  OUT  EUP3226 The external resistive divider is connected to the output, allowing remote voltage sensing as shown below. Thermal Considerations To avoid the EUP3226 from exceeding the maximum junction temperature, the user will need to do a thermal analysis. The goal of the thermal analysis is to determine whether the operating conditions exceed the maximum junction temperature of the part. The temperature rise is given by: TR=(PD)(θJA) Where PD=ILOAD2 × RDS(ON) is the power dissipated by the regulator ; θJA is the thermal resistance from the junction of the die to the ambient temperature. The junction temperature, TJ, is given by: TJ=TA+TR Where TA is the ambient temperature. TJ should be below the maximum junction temperature of 150°C. PC Board Layout Checklist For all switching power supplies, the layout is an important step in the design especially at high peak currents and switching frequencies. If the layout is not carefully done, the regulator might show stability problems as well as EMI problems. When laying out the printed circuit board, the following guidelines should be used to ensure proper operation of the EUP3226. 1. The input capacitor CIN should connect to PVIN as closely as possible. This capacitor provides the AC current to the internal power MOSFETs. 2. The power traces, consisting of the GND trace, the LX trace and the VIN trace should be kept short, direct and wide. 3. The FB pin should connect directly to the feedback resistors. The resistive divider RFB1/RFB2 must be connected between the COUT and ground. 4. Keep the switching node, LX, away from the sensitive FB node. DS3226 Ver1.0 June 2014 11 EUP3226 Packaging Information TDFN-10 Remark: Exposed pad outline drawing is for reference only. SYMBOLS Ver1.0 INCHES MIN. Normal MAX. MIN. Normal MAX. A 0.70 0.75 0.80 0.028 0.030 0.031 A1 0.00 - 0.05 0.000 - 0.002 D 2.90 3.00 3.10 0.114 0.118 0.122 D1 2.30 2.60 2.65 0.091 0.102 0.104 E 2.90 3.00 3.10 0.114 0.118 0.122 E1 1.50 1.65 1.75 0.059 0.065 0.069 L 0.30 0.40 0.50 0.012 0.016 0.020 b 0.18 - 0.30 0.007 - 0.012 e DS3226 MILLIMETERS June 2014 0.50 REF 0.020 REF 12 EUP3226 SOP-8 (EP) Remark: Exposed pad outline drawing is for reference only. SYMBOLS Ver1.0 INCHES MIN. Normal MAX. MIN. Normal A 1.35 - 1.75 0.053 - 0.069 A1 0.00 - 0.25 0.000 - 0.010 MAX. D 4.80 4.90 5.00 0.189 0.193 0.197 E1 3.70 3.90 4.00 0.146 0.154 0.157 D1 2.67 2.97 3.50 0.105 0.117 0.138 E2 1.78 2.18 2.60 0.070 0.086 0.102 E 5.80 6.00 6.20 0.228 0.236 0.244 L 0.40 - 1.27 0.016 - 0.050 b 0.31 - 0.51 0.012 - 0.020 e DS3226 MILLIMETERS June 2014 1.27 REF 0.050 REF 13